Cartridge filters in the energy and biomass industry

A cartridge filter is an efficient dry filter system to separate suspended solids as well as vapours and mist from air, thanks to micro-perforated pleated textile filter cartridges. Cartridge filters are also used in the energy and biomass industry to de-dust air. Especially around biomass plants where fine dust is always a challenge. The rectangular design of the filter installation enables the treatment of a wide range of pollutants and air volumes. A cartridge filter is very efficient for fine dust (< 500 micron).

The aerodynamic filter inlet consists of a pre-chamber, which reduces the air velocity by widening and thus minimizes the wear of the cartridges. A series of collision plates ensures that the larger coarse dust particles are separated immediately. Depending on the degree of contamination, an additional cyclone can also be used as a pre-separator. The air flow is distributed over the entire filter element surface and crosses it from outside to inside. Once filtered and cleaned, the air is transported to the filter outlet. The dust deposited on the external surface of the filter elements produces a uniform layer of dust that improves filtration efficiency.

In order to achieve very low dust emissions, the cartridge filter can be additionally equipped with a HEPA (H13) absolute filter. It is also possible to select the most optimal height to width ratio of the filter installation by placing the filter cartridges horizontally or vertically in the filter. A cartridge filter in the energy and biomass industry is therefore assembled and configured according to customer specific requirements.

From an aerodynamic point of view the pressure drop will gradually increase due to the contamination, a sensor measures this differential pressure over the filter elements and controls the filter cleaning system. This periodic cleaning of the filter elements is done by a strong compressed air pulse, this way the differential pressure stays within the selected limits. The compressed air pulse cleaning system blows the cartridges clean from the inside out. As a result, less compressed air is consumed and the filters will last longer.

The biomass dust is separated from the filter element surface and falls by gravity to the bottom of the filter hopper where it is collected in a bin. This collection bin is emptied periodically. Depending on the application, the hopper at the bottom of the filter is equipped with a rotating sluice to continuously discharge the powder and collect it in a big-bag, for example. It is also possible to use a conveyor screw to continuously discharge the dust to a container.